Rotary pump



Sept. 14, 1943. R, BRENNAN 2,329,386

ROTARY PUMP Filed Feb. 77, 1942 2 .3 3p 4 cf 1 I 2 I I /0 35 W I E/INVENTOR ROBERT B RENNAN v QTILW? L ATTYS,

Patented Sept. 14, 1943 2,329,386 ROTARY PUMP Robert Brennan, Auckland,New Zcaland Application February 7, 1942, Serial No. 429,941 In NewZealand November 8, 1940 1 Claim.

This invention relates to a pump construction of known type in which thepumping elements comprise the combination of a cylindrical stator memberand a rotor member arranged axially within the stator, shaped withco-operating surfaces of helical formation, and one of which surfaces ismade of a flexible nature. The rotation of the rotor member within 'thestator, while such rotor member is restrained from longitudinalmovement, causes a displacement of fluid from one end of the stator tothe other and performs the pumping action.

The rotor is driven by axial longitudinal connection through universalor flexible joints, with a driving shaft to which rotation is imparted.In the operations of the rotor therefore, a longitudinal re-action uponthe rotor takes place and this re-action tends to displace the rotoraxially within the stator. Consequently in the general construction ofthe pump, means must be provided to counteract this tendency todisplacement which is in effect a thrust upon the rotor drivingconnections and upon their bearings. In the restricted space availableand also because of the difiiculty of lubrication, this thrust load is avery undesirable factor in respect of this class of pump. Any means forrelieving the joints from this load would greatly increase theefficiency of the pump and help to eliminate excessive wear.

The present invention has been devised with the object of providing forthe balancing of the end thrust upon the rotor and its associated partsand also for the doubling of the capacity of the pump as concerned withthe diameter of the rotor.

The invention comprises, therefore, a construction of pump of this classin which the stator and rotor members are duplicated in longitudinal endto end association. and in which each unit combination of rotor andstator has its helical formation formed or arranged in opposition tothat of the other. Thus one unit combination is made with a left handhelix and the other with a right hand helix. This duplicated arrangementis combined with a cylinder construction under which the adjacent andinner ends of the two units open from an inlet chamber, and the remoteand outer ends, open to a common outlet, to provide for each unit actingto convey or pump the fluid from the inlet to the outlet. The respectiverelative positions of the inlet and outlet may, however, be reversed.

The invention also comprises means for the conveyance of rotation to.the said duplicated rotor.

In fully describing the invention, reference will be made to theaccompanying sheet of drawings, in which- Figure l is a sectional planof the complete pump, the rotor, however, being shown in plan.

Figures 2, 3 and 4 are cross sections upon the respective lines 2-2, 3-3and 44 of Figure 1, in all cases looking to the right of the said lines.

Figure 5 is a side elevation of the complete pump.

Figure 6 is a longitudinal section on an enlarged scale, of the'double rtwo ended rotor and showing means for the connection of the drivingspindle thereto.

In giving effect to the invention a compound or duplicated rotor memberis provided having a medial portion I0 and ends I I and I! each formedof the helical nature common to this known type of rotary pump, but somade that the helix of one is of right hand nature while that of theother end is of left hand, or opposed nature. In

the form shown, this rotor member is made (as shown in Figure 6) hollowthroughout its length and its driving spindle I3 is caused to pass inthrough one end of the hollow and has its end connected with the medialportion III by means of a suitable universal joint l4, so formed as toensure of the joint being kept liquid tight as by surrounding the jointby the sleeve I5. Into the other end of the hollow a plunger I6 isfitted and outside this a spring I! is arranged in compression betweenthe plunger and a plug I 8 screwed into the hollow end. The space withinthe plunger is packed with a suitable lubricant and-such lubricant isforced by the plunger and spring, in around the universal joint H tokeep it lubricated. A washer l9 of leather or other suitable material isarranged around the spindle I3 upon the other side of the joint I4 tokeep the lubricant from passing out through the other end of the hollow.

This duplicate rotor member has each helical end enclosed within astator member 20-2l respectively. Such stator is of the usual flexiblenature, generally being formed of rubber, characteristic of these pumpsand the stator for each end has its helical groove made incorrespondence with the rotor end associated therewith to effect thepumping action by which liquid may be passed, or forced, through thestator from one end to the other. As the two ends and their stators areformed with opposing helices the course of the liquid in each instanceis in an opposite direction to that of the other. Consequently bymounting the rotor and its stators within a suitable arrangement ofchambers, provision may be made for liquid led into the space betweenthe two stators being pumped out through both stators and deliveredthrough their outer ends, or reversely, liquid may be pumped from theouter ends and delivered at their inner ends.

It will be apparent that in such an arrangement of rotor and stators,the two ends being opposition one to the other in respect of thelongitudinal thrust on the members in the pumping, there is an absenceof any resultant lengthwise thrust on the rotor as a whole. Consequentlythere is also an absence of thrust upon the driving spindle and itsbearings. The power required to drive the rotor is therefore lessened inrelation to the pumps capacity, while with a given diameter of rotor,the pumps capacity is doubled as compared with that of a pump having theusual single rotor.

The construction and arrangement of cylinder and chambers for themounting of the said rotor and stators. as shown in the drawing,comprise a block 22 formed with an open ended inlet chamber 23 in itscentre and into which chamber an inlet port 24 opens from one side ofthe block, and also formed with an outlet chamber 25, divided from theinlet chamber by a partition member 26, and which chamber 25 alsoopens-to both ends of the block and has an outlet port 21 leading outthrough the block side opposite that on which the inlet port issituated. On each end of the block a cylinder 28 is fitted to extendoutward, such cylinder having a bore 29 which coincides with and opensto the end of the inlet chamber 23 and also being formed with a separatepassage 30 in its wall extending longitudinally throughout the samelength as that of the bore and which passage at its inner end coincideswith and opens to the corresponding end of the outlet chamber 25. Eachcylinder at its outer end extends beyond the outer ends of the bore 29and passage 30 to provide a connection between such ends. One cylinderhas its outer end closed while the other cylinder is formed at its outerend with a gland bearing 3| through which the driving spindle 13 of therotor is designed to be passed.

The compound or duplicated rotor is disposed to extend across the inletchamber 23 of the block 2| so that its medial portion I is positioned insuch chamber and its two helical ends H and i2 extend into therespective bores 29 of the two cylinders. Into the inner end of eachcylinder bore the corresponding stator member --2l is fitted to surroundits associated portion of the rotor. Such stator is secured in positionby forming it with a flange 32 on its inner end which engages with ashoulder 33 surrounding the bore end and which flange is then clamped bythe fastening of the cylinder end to the block 22, to thereby effect acomposite and firm assembly of the whole.

This assembly is supported upon any suitable base plate 34 and such baseplate may have combined therewith at one end a standard bearing 35 toreceive the end of the power shaft 36 which also passes in through thegland 3|. This power shaft is connected by any approved form ofuniversal joint 31 with the outer end of the driving spindle l3 toeffect the driving of the pump rotor in the manner characteristic ofpumps of this nature.

The rotation of the rotor in the required direction will cause liquid tobe drawn in through the inlet port 24 into the chamber 23, and thenforced out by both rotor ends to the outer ends of the respectivecylinders and then to pass through the passages 30 to the outlet chamber25 and out through the port 21.

In order to provide for the continuous lubrication of the rotor andstatorsby the passage'of liquid through them should the inlet supplyfail for any cause, provision is made for the re-circulation of theliquid remaining in the pump in such a circumstance. For this purpose ahole 38 is formed in the partition member 26 dividing the inlet chamber23 from the outlet chamber 25. The operations of the rotor will thuscause the liquid to be circulated from the inlet chamber through thecylinders and back from the outlet chamber again to the inlet chamber.

Other ways of connecting the rotor with the I power shaft through thedriving spindle l3 may be employed without departing from the spirit ofthe invention. The manner of connection shown in the drawing by whichthe driving spindle is connected to the rotor at about midway in itslength is preferred as providing for the rotative power beingdistributed evenly to both rotor ends.

I claim:

A rotary pump comprising a pair of cylindrical stator members eachhaving an internal helical surface, a rotor member extending axiallythrough the stator members, said motor having a helical surface at eachend thereof co-operating with and corresponding to the helical surfacesof the stator members and being hollow throughout its length, an inletfor one open end of each stator, an outlet for the other open end ofeach stator, a chamber communicating with the outer ends of the twostators, a drive shaft, a universal joint in the hollow portion of therotor member at the approximate intermediate point of the length thereofconnecting said shaft to the rotor member to rotate the latter, andmeans in the hollow portion of the rotor to lubricate the universaljoint.

' ROBERT BRENNAN.

